Add invite-only group classes

Group classes can now be marked invite-only (us_offerings.access_mode).
Invite-only classes are hidden from the public catalog and reachable only
when the instructor lets someone in via one of three paths, managed from
My Lessons -> My Group Classes:

- Add students directly: enrols them now with a pending payment.
- Make available: grants registered students access to self-enrol through
  the normal paid flow (multi-select, emailed a notice).
- Invite by email: tokenised registration invite tied to the class for a
  non-account address; after they register the class becomes enrollable.
  Reuses an existing pending invite instead of sending a second link.

New us_group_access table records grants; GET /offerings merges granted
invite-only classes for the caller; enrolment requires a grant
(403 invite_required) and flips it to enrolled on success.

composer test (487), composer lint, composer cs all pass.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/AdminMenu.php

@@ -18,6 +18,7 @@ use Unsupervised\Schedular\Auth\StudentHistory;
 use Unsupervised\Schedular\Booking\BookingRepository;
 use Unsupervised\Schedular\Booking\LessonController;
 use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
+use Unsupervised\Schedular\GroupClass\GroupAccessRepository;
 use Unsupervised\Schedular\GroupClass\GroupClassController;
 use Unsupervised\Schedular\Offering\OfferingController;
 use Unsupervised\Schedular\Offering\OfferingRepository;
@@ -53,15 +54,15 @@ class AdminMenu {
 	private PaymentController $paymentController;
 	private PaymentReportController $paymentReportController;
 
-	public function __construct( AvailabilityRepository $availability, BookingRepository $bookings, OfferingRepository $offerings, QuestionRepository $questions, AnswerRepository $answers, PolicyRepository $policies, PolicyVersionRepository $policyVersions, PolicyService $policyService, AcceptanceRepository $acceptances, InviteRepository $invites, EnrollmentRepository $enrollments, StudioSettings $settings, PaymentRepository $payments, PaymentService $paymentService, BillingMethodResolver $resolver ) {
+	public function __construct( AvailabilityRepository $availability, BookingRepository $bookings, OfferingRepository $offerings, QuestionRepository $questions, AnswerRepository $answers, PolicyRepository $policies, PolicyVersionRepository $policyVersions, PolicyService $policyService, AcceptanceRepository $acceptances, InviteRepository $invites, EnrollmentRepository $enrollments, GroupAccessRepository $groupAccess, StudioSettings $settings, PaymentRepository $payments, PaymentService $paymentService, BillingMethodResolver $resolver, RegistrationMailer $registrationMailer ) {
 		$this->availabilityController         = new AvailabilityController( $availability, $offerings );
 		$this->lessonController               = new LessonController( $bookings, $payments, $availability );
 		$this->offeringController             = new OfferingController( $offerings );
 		$this->questionController             = new QuestionController( $questions, $offerings );
 		$this->policyController               = new PolicyController( $policies, $policyVersions, $policyService );
 		$this->registrationController         = new RegistrationController( $invites );
-		$this->registrationApprovalController = new RegistrationApprovalController( new RegistrationMailer() );
-		$this->groupClassController           = new GroupClassController( $enrollments, $offerings, $payments );
+		$this->registrationApprovalController = new RegistrationApprovalController( $registrationMailer );
+		$this->groupClassController           = new GroupClassController( $enrollments, $offerings, $payments, $groupAccess, $paymentService, $invites, $registrationMailer );
 		$this->studentController              = new StudentController( $bookings, $availability, $offerings, $enrollments, $resolver, new StudentHistory( $acceptances, $policies, $policyVersions, $answers, $questions, $payments ), new StudentActions( $bookings, $availability, $enrollments, $paymentService ) );
 		$this->instructorController           = new InstructorController();
 		$this->settings                       = $settings;

src/Auth/Invite.php

@@ -51,6 +51,7 @@ class Invite {
 		public readonly ?string $createdAt = null,
 		public readonly string $kind = self::KIND_PERSONAL,
 		public readonly ?string $expiresAt = null,
+		public readonly ?int $offeringId = null,
 		public readonly ?int $id = null,
 	) {}
 
@@ -66,6 +67,7 @@ class Invite {
 			createdAt:      Val::stringOrNull( $row->created_at ?? null ),
 			kind:           '' !== Val::string( $row->kind ?? '' ) ? Val::string( $row->kind ) : self::KIND_PERSONAL,
 			expiresAt:      Val::stringOrNull( $row->expires_at ?? null ),
+			offeringId:     Val::intOrNull( $row->offering_id ?? null ),
 			id:             Val::int( $row->id ),
 		);
 	}
@@ -132,6 +134,7 @@ class Invite {
 			'accepted_user_id' => $this->acceptedUserId,
 			'accepted_at'      => $this->acceptedAt,
 			'expires_at'       => $this->expiresAt,
+			'offering_id'      => $this->offeringId,
 		];
 	}
 }

src/Auth/InviteRepository.php

@@ -23,6 +23,7 @@ class InviteRepository {
 				'token'            => $invite->token,
 				'role'             => $invite->role,
 				'kind'             => $invite->kind,
+				'offering_id'      => $invite->offeringId,
 				'status'           => $invite->status,
 				'invited_by'       => $invite->invitedBy,
 				'accepted_user_id' => $invite->acceptedUserId,
@@ -30,7 +31,7 @@ class InviteRepository {
 				'accepted_at'      => $invite->acceptedAt,
 				'expires_at'       => $invite->expiresAt,
 			],
-			[ '%s', '%s', '%s', '%s', '%s', '%d', '%d', '%s', '%s', '%s' ]
+			[ '%s', '%s', '%s', '%s', '%d', '%s', '%d', '%d', '%s', '%s', '%s' ]
 		);
 
 		return false === $result ? 0 : $this->db->insert_id;

src/Auth/RegistrationMailer.php

@@ -105,6 +105,56 @@ class RegistrationMailer {
 		return (bool) wp_mail( $email, $subject, $body );
 	}
 
+	/**
+	 * Tell a registered student they have been given access to an invite-only
+	 * group class and can now enrol. Returns false when there is no recipient.
+	 */
+	public function sendClassAccessGranted( \WP_User $user, string $className ): bool {
+		if ( '' === (string) $user->user_email ) {
+			return false;
+		}
+
+		$subject = sprintf(
+			/* translators: %s: class title */
+			__( 'You have been invited to %s', 'unsupervised-schedular' ),
+			$className
+		);
+		$body = sprintf(
+			/* translators: 1: class title, 2: site name, 3: login URL */
+			__( "You have been given access to the group class \"%1\$s\" at %2\$s.\n\nLog in and open the group classes page to enrol:\n%3\$s", 'unsupervised-schedular' ),
+			$className,
+			$this->siteName(),
+			wp_login_url()
+		);
+
+		return (bool) wp_mail( $user->user_email, $subject, $body );
+	}
+
+	/**
+	 * Email a tokenised registration link to someone invited to a group class who
+	 * does not yet have an account. Returns false when there is no recipient.
+	 */
+	public function sendClassInvite( string $email, string $link, string $className ): bool {
+		if ( '' === $email ) {
+			return false;
+		}
+
+		$subject = sprintf(
+			/* translators: %s: class title */
+			__( 'You are invited to join %s', 'unsupervised-schedular' ),
+			$className
+		);
+		$body = sprintf(
+			/* translators: 1: class title, 2: site name, 3: registration URL */
+			__( "You have been invited to the group class \"%1\$s\" at %2\$s.\n\nCreate your account using this link, then choose to enrol in the class:\n%3\$s", 'unsupervised-schedular' ),
+			$className,
+			$this->siteName(),
+			$link
+		);
+
+		return (bool) wp_mail( $email, $subject, $body );
+	}
+
 	private function siteName(): string {
 		$name = (string) get_bloginfo( 'name' );
 

src/Auth/RegistrationPage.php

@@ -3,6 +3,7 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\GroupClass\GroupAccessRepository;
 use Unsupervised\Schedular\Payment\StudioSettings;
 use Unsupervised\Schedular\Policy\AcceptanceRepository;
 use Unsupervised\Schedular\Policy\Policy;
@@ -38,6 +39,7 @@ class RegistrationPage {
 		private RegistrationMailer $mailer,
 		private QuestionRepository $questions,
 		private AnswerRepository $answers,
+		private GroupAccessRepository $access,
 	) {}
 
 	/**
@@ -203,6 +205,11 @@ class RegistrationPage {
 		if ( $inviteValid && ! $invite->isGroup() ) {
 			$this->invites->markAccepted( (int) $invite->id, (int) $userId );
 
+			// A personal invite may carry a group-class grant (invited by email);
+			// point any grants for this address at the new account so the class
+			// becomes enrollable for them.
+			$this->access->linkStudentByEmail( $email, (int) $userId );
+
 			wp_set_current_user( (int) $userId );
 			wp_set_auth_cookie( (int) $userId );
 

src/GroupClass/EnrollmentEndpoint.php

@@ -19,6 +19,7 @@ class EnrollmentEndpoint {
 		private OfferingRepository $offerings,
 		private RegistrationGate $gate,
 		private PaymentService $payments,
+		private GroupAccessRepository $access,
 	) {}
 
 	/**
@@ -88,6 +89,12 @@ class EnrollmentEndpoint {
 			return new \WP_Error( 'already_enrolled', __( 'You are already enrolled in this class.', 'unsupervised-schedular' ), [ 'status' => 409 ] );
 		}
 
+		// Invite-only classes can only be enrolled in by students who were granted
+		// access (or added directly); everyone else never sees the class at all.
+		if ( $offering->isInviteOnly() && ! $this->access->hasGrant( $offeringId, $studentId ) ) {
+			return new \WP_Error( 'invite_required', __( 'This class is by invitation only.', 'unsupervised-schedular' ), [ 'status' => 403 ] );
+		}
+
 		if ( null !== $offering->capacity && $this->enrollments->countActiveForOffering( $offeringId ) >= $offering->capacity ) {
 			return new \WP_Error( 'class_full', __( 'This class is full.', 'unsupervised-schedular' ), [ 'status' => 409 ] );
 		}
@@ -110,6 +117,12 @@ class EnrollmentEndpoint {
 
 		$this->gate->record( PolicyAcceptance::REG_ENROLLMENT, $id, $studentId, $offeringId, $answers, $acceptedVersionIds, $this->clientIp() );
 
+		// Mark the access grant used so instructor rosters distinguish invited
+		// students from enrolled ones (a no-op for public classes).
+		if ( $offering->isInviteOnly() ) {
+			$this->access->markEnrolled( $offeringId, $studentId );
+		}
+
 		$payment = null;
 		if ( $offering->price > 0.0 ) {
 			$payment = $this->payments->createForRegistration( Payment::REG_ENROLLMENT, $id, $studentId, $offering->instructorId, $offering->price, $offering->currency, $offering->etransferEmail );

src/GroupClass/GroupAccess.php

@@ -0,0 +1,67 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\GroupClass;
+
+use Unsupervised\Schedular\Val;
+
+/**
+ * A grant of access to an invite-only group class. Registered students who have
+ * been "made available" a class hold an `invited` grant (`student_id` set);
+ * email-invited people who do not yet have an account hold a grant keyed by
+ * `email` and linked to a `us_invites` row, which is pointed at the new
+ * `student_id` once they register. A grant flips to `enrolled` when the student
+ * enrols through the normal flow.
+ */
+class GroupAccess {
+
+	public const STATUS_INVITED  = 'invited';
+	public const STATUS_ENROLLED = 'enrolled';
+	public const STATUS_REVOKED  = 'revoked';
+
+	/**
+	 * All valid grant statuses.
+	 *
+	 * @var list<string>
+	 */
+	public const VALID_STATUSES = [ self::STATUS_INVITED, self::STATUS_ENROLLED, self::STATUS_REVOKED ];
+
+	public function __construct(
+		public readonly int $offeringId,
+		public readonly ?int $studentId = null,
+		public readonly string $email = '',
+		public readonly ?int $inviteId = null,
+		public readonly string $status = self::STATUS_INVITED,
+		public readonly ?int $invitedBy = null,
+		public readonly ?int $id = null,
+	) {}
+
+	public static function fromRow( \stdClass $row ): self {
+		return new self(
+			offeringId: Val::int( $row->offering_id ),
+			studentId:  Val::intOrNull( $row->student_id ),
+			email:      Val::string( $row->email ?? '' ),
+			inviteId:   Val::intOrNull( $row->invite_id ?? null ),
+			status:     Val::string( $row->status ),
+			invitedBy:  Val::intOrNull( $row->invited_by ?? null ),
+			id:         Val::int( $row->id ),
+		);
+	}
+
+	/**
+	 * Returns a plain array representation of the grant.
+	 *
+	 * @return array<string, mixed>
+	 */
+	public function toArray(): array {
+		return [
+			'id'          => $this->id,
+			'offering_id' => $this->offeringId,
+			'student_id'  => $this->studentId,
+			'email'       => $this->email,
+			'invite_id'   => $this->inviteId,
+			'status'      => $this->status,
+			'invited_by'  => $this->invitedBy,
+		];
+	}
+}

src/GroupClass/GroupAccessRepository.php

@@ -0,0 +1,132 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\GroupClass;
+
+class GroupAccessRepository {
+
+	private string $table;
+
+	public function __construct( private \wpdb $db ) {
+		$this->table = $db->prefix . 'us_group_access';
+	}
+
+	public function insert( GroupAccess $access ): int {
+		$this->db->insert(
+			$this->table,
+			[
+				'offering_id' => $access->offeringId,
+				'student_id'  => $access->studentId,
+				'email'       => $access->email,
+				'invite_id'   => $access->inviteId,
+				'status'      => $access->status,
+				'invited_by'  => $access->invitedBy,
+				'created_at'  => current_time( 'mysql' ),
+			],
+			[ '%d', '%d', '%s', '%d', '%s', '%d', '%s' ]
+		);
+
+		return $this->db->insert_id;
+	}
+
+	/**
+	 * Whether a student holds a live (invited or enrolled) grant for an offering.
+	 */
+	public function hasGrant( int $offeringId, int $studentId ): bool {
+		$count = (int) $this->db->get_var(
+			$this->db->prepare(
+				'SELECT COUNT(*) FROM %i WHERE offering_id = %d AND student_id = %d AND status IN ( %s, %s )',
+				$this->table,
+				$offeringId,
+				$studentId,
+				GroupAccess::STATUS_INVITED,
+				GroupAccess::STATUS_ENROLLED
+			)
+		);
+
+		return $count > 0;
+	}
+
+	/**
+	 * The offering ids a student holds a live grant for — the invite-only classes
+	 * to fold into their catalogue view.
+	 *
+	 * @return list<int>
+	 */
+	public function findGrantedOfferingIds( int $studentId ): array {
+		$rows = $this->db->get_col(
+			$this->db->prepare(
+				'SELECT DISTINCT offering_id FROM %i WHERE student_id = %d AND status IN ( %s, %s )',
+				$this->table,
+				$studentId,
+				GroupAccess::STATUS_INVITED,
+				GroupAccess::STATUS_ENROLLED
+			)
+		);
+
+		return array_values( array_map( \Unsupervised\Schedular\Val::int( ... ), $rows ) );
+	}
+
+	/**
+	 * All grants for an offering, newest first.
+	 *
+	 * @return list<GroupAccess>
+	 */
+	public function findByOffering( int $offeringId ): array {
+		$rows = $this->db->get_results(
+			$this->db->prepare(
+				'SELECT * FROM %i WHERE offering_id = %d ORDER BY id DESC',
+				$this->table,
+				$offeringId
+			)
+		);
+
+		return array_map( GroupAccess::fromRow( ... ), $rows ?? [] );
+	}
+
+	/**
+	 * Point email-invite grants for an address at the account created when the
+	 * invitation was accepted, so the granted class unlocks for the new student.
+	 * Only grants still awaiting an account (`student_id` NULL) are linked.
+	 */
+	public function linkStudentByEmail( string $email, int $studentId ): bool {
+		if ( '' === $email ) {
+			return false;
+		}
+
+		$sql = $this->db->prepare(
+			'UPDATE %i SET student_id = %d WHERE email = %s AND student_id IS NULL',
+			$this->table,
+			$studentId,
+			$email
+		);
+
+		return null !== $sql && false !== $this->db->query( $sql );
+	}
+
+	/**
+	 * Flip a student's live grant for an offering to enrolled.
+	 */
+	public function markEnrolled( int $offeringId, int $studentId ): bool {
+		return false !== $this->db->update(
+			$this->table,
+			[ 'status' => GroupAccess::STATUS_ENROLLED ],
+			[
+				'offering_id' => $offeringId,
+				'student_id'  => $studentId,
+			],
+			[ '%s' ],
+			[ '%d', '%d' ]
+		);
+	}
+
+	public function revoke( int $id ): bool {
+		return false !== $this->db->update(
+			$this->table,
+			[ 'status' => GroupAccess::STATUS_REVOKED ],
+			[ 'id' => $id ],
+			[ '%s' ],
+			[ '%d' ]
+		);
+	}
+}

src/GroupClass/GroupClassController.php

@@ -3,10 +3,17 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\GroupClass;
 
+use Unsupervised\Schedular\Auth\Invite;
+use Unsupervised\Schedular\Auth\InviteRepository;
+use Unsupervised\Schedular\Auth\RegistrationController;
+use Unsupervised\Schedular\Auth\RegistrationMailer;
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Offering\Offering;
 use Unsupervised\Schedular\Offering\OfferingRepository;
+use Unsupervised\Schedular\Payment\Payment;
 use Unsupervised\Schedular\Payment\PaymentRepository;
+use Unsupervised\Schedular\Payment\PaymentService;
+use Unsupervised\Schedular\Val;
 
 class GroupClassController {
 
@@ -14,6 +21,10 @@ class GroupClassController {
 		private EnrollmentRepository $enrollments,
 		private OfferingRepository $offerings,
 		private PaymentRepository $payments,
+		private GroupAccessRepository $access,
+		private PaymentService $paymentService,
+		private InviteRepository $invites,
+		private RegistrationMailer $mailer,
 	) {}
 
 	public function renderPage(): void {
@@ -41,7 +52,8 @@ class GroupClassController {
 	/**
 	 * Instructor view: their own group classes with per-class rosters. Each class
 	 * shows its enrolment count against capacity plus a roster of enrolled
-	 * students with enrolment and payment status.
+	 * students with enrolment and payment status. Invite-only classes also carry
+	 * controls to add, grant access to, or email-invite students.
 	 */
 	public function renderInstructorPage(): void {
 		if ( ! current_user_can( RoleManager::CAP_VIEW_LESSONS ) ) {
@@ -49,7 +61,13 @@ class GroupClassController {
 		}
 
 		$instructorId = get_current_user_id();
-		$enrollments  = $this->enrollments->findByInstructor( $instructorId );
+
+		$notice = '';
+		if ( isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_group_action' ) ) {
+			$notice = $this->handleFormAction( $instructorId );
+		}
+
+		$enrollments = $this->enrollments->findByInstructor( $instructorId );
 
 		$classes = array_map(
 			function ( Offering $offering ) use ( $enrollments ): array {
@@ -76,15 +94,280 @@ class GroupClassController {
 				}
 
 				return [
-					'title'    => $offering->title,
-					'capacity' => $offering->capacity,
-					'enrolled' => $enrolled,
-					'roster'   => $roster,
+					'id'          => $offering->id,
+					'title'       => $offering->title,
+					'capacity'    => $offering->capacity,
+					'enrolled'    => $enrolled,
+					'invite_only' => $offering->isInviteOnly(),
+					'roster'      => $roster,
+					'invited'     => $offering->isInviteOnly() ? $this->pendingInvites( (int) $offering->id ) : [],
 				];
 			},
 			$this->offerings->findAll( $instructorId, Offering::KIND_GROUP_CLASS )
 		);
 
+		$students = $this->studentOptions();
+
 		include USC_PLUGIN_DIR . 'templates/admin/my-group-classes.php';
 	}
+
+	/**
+	 * Pending (not-yet-enrolled) access grants for an invite-only class, shown so
+	 * the instructor can see who has been invited but has not enrolled yet.
+	 *
+	 * @return list<array{who: string, kind: string}>
+	 */
+	private function pendingInvites( int $offeringId ): array {
+		$out = [];
+		foreach ( $this->access->findByOffering( $offeringId ) as $grant ) {
+			if ( GroupAccess::STATUS_INVITED !== $grant->status ) {
+				continue;
+			}
+
+			if ( null !== $grant->studentId ) {
+				$user  = get_userdata( $grant->studentId );
+				$out[] = [
+					'who'  => $user ? $user->display_name : (string) $grant->studentId,
+					'kind' => __( 'Granted', 'unsupervised-schedular' ),
+				];
+			} else {
+				$out[] = [
+					'who'  => $grant->email,
+					'kind' => __( 'Email invite', 'unsupervised-schedular' ),
+				];
+			}
+		}
+
+		return $out;
+	}
+
+	/**
+	 * Handle a posted management action, returning a status notice for display.
+	 * Every action is scoped to a group class the current instructor owns.
+	 */
+	private function handleFormAction( int $instructorId ): string {
+		// Nonce is verified by the caller before this method runs.
+		// phpcs:disable WordPress.Security.NonceVerification.Missing
+		$action     = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
+		$offeringId = absint( Val::int( $_POST['offering_id'] ?? 0 ) );
+		$offering   = $offeringId > 0 ? $this->offerings->findById( $offeringId ) : null;
+
+		if ( null === $offering || $offering->instructorId !== $instructorId || Offering::KIND_GROUP_CLASS !== $offering->kind ) {
+			return esc_html__( 'That group class was not found.', 'unsupervised-schedular' );
+		}
+
+		if ( 'add_direct' === $action ) {
+			return $this->addDirect( $offering, $this->postedStudentIds() );
+		}
+
+		if ( 'grant_access' === $action ) {
+			return $this->grantAccess( $offering, $this->postedStudentIds() );
+		}
+
+		if ( 'invite_email' === $action ) {
+			$email = sanitize_email( Val::string( wp_unslash( $_POST['email'] ?? '' ) ) );
+
+			return $this->inviteEmail( $offering, $email );
+		}
+		// phpcs:enable WordPress.Security.NonceVerification.Missing
+
+		return '';
+	}
+
+	/**
+	 * Directly enrol registered students, each with a pending payment at the
+	 * class price (comp students are settled immediately by the payment service).
+	 *
+	 * @param list<int> $studentIds
+	 */
+	private function addDirect( Offering $offering, array $studentIds ): string {
+		$added = 0;
+		foreach ( $studentIds as $studentId ) {
+			if ( $this->enrollments->hasActiveEnrollment( (int) $offering->id, $studentId ) ) {
+				continue;
+			}
+
+			$enrollmentId = $this->enrollments->insert(
+				new Enrollment(
+					offeringId:   (int) $offering->id,
+					studentId:    $studentId,
+					instructorId: $offering->instructorId,
+				)
+			);
+
+			if ( $offering->price > 0.0 ) {
+				$payment = $this->paymentService->createForRegistration(
+					Payment::REG_ENROLLMENT,
+					$enrollmentId,
+					$studentId,
+					$offering->instructorId,
+					$offering->price,
+					$offering->currency,
+					$offering->etransferEmail
+				);
+
+				if ( null !== $payment && null !== $payment->id ) {
+					$this->enrollments->setPaymentId( $enrollmentId, $payment->id );
+				}
+			}
+
+			$this->access->markEnrolled( (int) $offering->id, $studentId );
+			++$added;
+		}
+
+		/* translators: %d: number of students added. */
+		return sprintf( esc_html__( '%d student(s) added to the class.', 'unsupervised-schedular' ), $added );
+	}
+
+	/**
+	 * Grant registered students access to the class so it appears in their list
+	 * for self-enrolment, notifying each by email.
+	 *
+	 * @param list<int> $studentIds
+	 */
+	private function grantAccess( Offering $offering, array $studentIds ): string {
+		$granted = 0;
+		foreach ( $studentIds as $studentId ) {
+			if (
+				$this->enrollments->hasActiveEnrollment( (int) $offering->id, $studentId )
+				|| $this->access->hasGrant( (int) $offering->id, $studentId )
+			) {
+				continue;
+			}
+
+			$this->access->insert(
+				new GroupAccess(
+					offeringId: (int) $offering->id,
+					studentId:  $studentId,
+					status:     GroupAccess::STATUS_INVITED,
+					invitedBy:  get_current_user_id(),
+				)
+			);
+
+			$user = get_userdata( $studentId );
+			if ( $user instanceof \WP_User ) {
+				$this->mailer->sendClassAccessGranted( $user, $offering->title );
+			}
+
+			++$granted;
+		}
+
+		/* translators: %d: number of students granted access. */
+		return sprintf( esc_html__( '%d student(s) granted access.', 'unsupervised-schedular' ), $granted );
+	}
+
+	/**
+	 * Invite someone by email. A registered address is treated as a grant; an
+	 * unknown address gets a tokenised registration invite tied to the class,
+	 * reusing any pending invite already outstanding for that address (in which
+	 * case no new link is sent).
+	 */
+	private function inviteEmail( Offering $offering, string $email ): string {
+		if ( ! is_email( $email ) ) {
+			return esc_html__( 'Enter a valid email address.', 'unsupervised-schedular' );
+		}
+
+		$existingUserId = email_exists( $email );
+		if ( false !== $existingUserId ) {
+			return $this->grantAccess( $offering, [ (int) $existingUserId ] );
+		}
+
+		// Reuse an outstanding invite rather than mailing a second link; still
+		// attach a class grant so enrolment unlocks once they register.
+		$pending = $this->invites->findPendingByEmail( $email );
+		if ( null !== $pending ) {
+			$this->access->insert(
+				new GroupAccess(
+					offeringId: (int) $offering->id,
+					email:      $email,
+					inviteId:   $pending->id,
+					status:     GroupAccess::STATUS_INVITED,
+					invitedBy:  get_current_user_id(),
+				)
+			);
+
+			return esc_html__( 'This person already has a pending invitation; the class was added to it. No new link was sent.', 'unsupervised-schedular' );
+		}
+
+		$rawToken = wp_generate_password( 32, false );
+		$inviteId = $this->invites->insert(
+			new Invite(
+				email:      $email,
+				token:      Invite::hashToken( $rawToken ),
+				invitedBy:  get_current_user_id(),
+				offeringId: (int) $offering->id,
+			)
+		);
+
+		if ( $inviteId <= 0 ) {
+			return esc_html__( 'Could not create the invite. Deactivate and reactivate the plugin to update the database, then try again.', 'unsupervised-schedular' );
+		}
+
+		$this->access->insert(
+			new GroupAccess(
+				offeringId: (int) $offering->id,
+				email:      $email,
+				inviteId:   $inviteId,
+				status:     GroupAccess::STATUS_INVITED,
+				invitedBy:  get_current_user_id(),
+			)
+		);
+
+		$this->mailer->sendClassInvite( $email, $this->registrationLink( $rawToken ), $offering->title );
+
+		return esc_html__( 'Invitation sent.', 'unsupervised-schedular' );
+	}
+
+	/**
+	 * Registered students to offer in the add/grant selects, by display name.
+	 *
+	 * @return list<array{id: int, name: string}>
+	 */
+	private function studentOptions(): array {
+		$users = array_filter(
+			get_users(
+				[
+					'role'    => RoleManager::STUDENT,
+					'orderby' => 'display_name',
+					'order'   => 'ASC',
+				]
+			),
+			static fn( mixed $u ): bool => $u instanceof \WP_User
+		);
+
+		return array_values(
+			array_map(
+				static fn( \WP_User $u ): array => [
+					'id'   => (int) $u->ID,
+					'name' => '' !== (string) $u->display_name ? (string) $u->display_name : (string) $u->user_email,
+				],
+				$users
+			)
+		);
+	}
+
+	/**
+	 * The de-duplicated positive student ids posted from a multi-select.
+	 *
+	 * @return list<int>
+	 */
+	private function postedStudentIds(): array {
+		// Nonce is verified by the caller before this method runs.
+		// phpcs:ignore WordPress.Security.NonceVerification.Missing, WordPress.Security.ValidatedSanitizedInput.MissingUnslash, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- each element is coerced to a positive int below; slashes cannot survive integer coercion.
+		$raw = (array) ( $_POST['student_ids'] ?? [] );
+		$ids = array_filter( array_map( static fn( mixed $v ): int => absint( Val::int( $v ) ), $raw ) );
+
+		return array_values( array_unique( $ids ) );
+	}
+
+	/**
+	 * Build the registration URL for a raw invite token, mirroring the invites
+	 * admin page so class invites land on the same registration page.
+	 */
+	private function registrationLink( string $rawToken ): string {
+		$pageId   = Val::int( get_option( RegistrationController::OPTION_PAGE, 0 ) );
+		$linkBase = $pageId > 0 ? (string) get_permalink( $pageId ) : '';
+
+		return add_query_arg( 'us_invite', rawurlencode( $rawToken ), '' !== $linkBase ? $linkBase : home_url( '/' ) );
+	}
 }

src/Offering/Offering.php

@@ -27,6 +27,19 @@ class Offering {
 	 */
 	public const VALID_BILLING_MODES = [ self::BILLING_ONE_TIME, self::BILLING_FULL_TERM ];
 
+	/** Listed in the public catalogue; anyone with `book_lesson` may enrol. */
+	public const ACCESS_PUBLIC = 'public';
+
+	/** Hidden from the catalogue; only invited/added students may enrol (group classes). */
+	public const ACCESS_INVITE_ONLY = 'invite_only';
+
+	/**
+	 * All valid access modes.
+	 *
+	 * @var list<string>
+	 */
+	public const VALID_ACCESS_MODES = [ self::ACCESS_PUBLIC, self::ACCESS_INVITE_ONLY ];
+
 	public function __construct(
 		public readonly int $instructorId,
 		public readonly string $kind,
@@ -43,10 +56,19 @@ class Offering {
 		public readonly ?string $scheduleNote = null,
 		public readonly ?string $etransferEmail = null,
 		public readonly ?int $cancellationCutoffHours = null,
+		public readonly string $accessMode = self::ACCESS_PUBLIC,
 		public readonly bool $isActive = true,
 		public readonly ?int $id = null,
 	) {}
 
+	/**
+	 * Whether the offering is hidden from the public catalogue and reachable
+	 * only by invited or directly-added students.
+	 */
+	public function isInviteOnly(): bool {
+		return self::ACCESS_INVITE_ONLY === $this->accessMode;
+	}
+
 	/**
 	 * Normalise a submitted term date to canonical `Y-m-d`, or null when it is
 	 * not a real calendar date. Round-trips through DateTimeImmutable so
@@ -85,6 +107,7 @@ class Offering {
 			scheduleNote:    Val::stringOrNull( $row->schedule_note ),
 			etransferEmail:  Val::stringOrNull( $row->etransfer_email ),
 			cancellationCutoffHours: Val::intOrNull( $row->cancellation_cutoff_hours ),
+			accessMode:      '' !== Val::string( $row->access_mode ?? '' ) ? Val::string( $row->access_mode ) : self::ACCESS_PUBLIC,
 			isActive:        Val::bool( $row->is_active ),
 			id:              Val::int( $row->id ),
 		);
@@ -116,6 +139,7 @@ class Offering {
 			'term_end'                  => $this->termEnd,
 			'schedule_note'             => $this->scheduleNote,
 			'cancellation_cutoff_hours' => $this->cancellationCutoffHours,
+			'access_mode'               => $this->accessMode,
 			'is_active'                 => $this->isActive,
 		];
 

src/Offering/OfferingController.php

@@ -135,6 +135,7 @@ class OfferingController {
 			scheduleNote:    $this->nullableText( sanitize_text_field( Val::string( wp_unslash( $_POST['schedule_note'] ?? '' ) ) ) ),
 			etransferEmail:  $this->nullableText( sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) ) ),
 			cancellationCutoffHours: $cutoffHours,
+			accessMode:      isset( $_POST['invite_only'] ) ? Offering::ACCESS_INVITE_ONLY : Offering::ACCESS_PUBLIC,
 			isActive:        isset( $_POST['is_active'] ),
 			id:              $existing?->id,
 		);

src/Offering/OfferingEndpoint.php

@@ -4,11 +4,15 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Offering;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\GroupClass\GroupAccessRepository;
 use Unsupervised\Schedular\Val;
 
 class OfferingEndpoint {
 
-	public function __construct( private OfferingRepository $repository ) {}
+	public function __construct(
+		private OfferingRepository $repository,
+		private GroupAccessRepository $access,
+	) {}
 
 	/**
 	 * Registers this endpoint's REST routes.
@@ -62,16 +66,53 @@ class OfferingEndpoint {
 	}
 
 	public function index( \WP_REST_Request $request ): \WP_REST_Response {
-		$offerings = $this->repository->findAll(
-			Val::int( $request->get_param( 'instructor_id' ) ),
-			Val::string( $request->get_param( 'kind' ) ),
-			activeOnly: true,
-		);
+		$instructorId = Val::int( $request->get_param( 'instructor_id' ) );
+		$kind         = Val::string( $request->get_param( 'kind' ) );
+
+		// The public catalogue is public offerings only; invite-only classes are
+		// hidden from it and surfaced separately to the students granted access.
+		$offerings = $this->repository->findAll( $instructorId, $kind, activeOnly: true, accessMode: Offering::ACCESS_PUBLIC );
+
+		foreach ( $this->grantedInviteOnly( $instructorId, $kind ) as $granted ) {
+			$offerings[] = $granted;
+		}
 
 		// Public listing: omit the private e-transfer destination email.
 		return new \WP_REST_Response( array_map( fn( Offering $o ) => $o->toArray( includeEtransferEmail: false ), $offerings ), 200 );
 	}
 
+	/**
+	 * The active invite-only offerings the caller has been granted access to,
+	 * matching the same instructor/kind filters as the public catalogue.
+	 *
+	 * @return list<Offering>
+	 */
+	private function grantedInviteOnly( int $instructorId, string $kind ): array {
+		$grantedIds = $this->access->findGrantedOfferingIds( get_current_user_id() );
+		if ( [] === $grantedIds ) {
+			return [];
+		}
+
+		$out = [];
+		foreach ( $grantedIds as $offeringId ) {
+			$offering = $this->repository->findById( $offeringId );
+
+			if (
+				null === $offering
+				|| ! $offering->isActive
+				|| ! $offering->isInviteOnly()
+				|| ( $instructorId > 0 && $offering->instructorId !== $instructorId )
+				|| ( '' !== $kind && $offering->kind !== $kind )
+			) {
+				continue;
+			}
+
+			$out[] = $offering;
+		}
+
+		return $out;
+	}
+
 	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
 		$title = sanitize_text_field( Val::string( $request->get_param( 'title' ) ) );
 		if ( '' === $title ) {
@@ -104,6 +145,7 @@ class OfferingEndpoint {
 			scheduleNote:    $this->nullableText( $request->get_param( 'schedule_note' ) ),
 			etransferEmail:  $this->nullableEmail( $request->get_param( 'etransfer_email' ) ),
 			cancellationCutoffHours: $this->nullableInt( $request->get_param( 'cancellation_cutoff_hours' ) ),
+			accessMode:      $this->accessMode( $request->get_param( 'access_mode' ), Offering::ACCESS_PUBLIC ),
 			isActive:        null === $request->get_param( 'is_active' ) ? true : (bool) $request->get_param( 'is_active' ),
 		);
 
@@ -150,6 +192,7 @@ class OfferingEndpoint {
 			scheduleNote:    $request->has_param( 'schedule_note' ) ? $this->nullableText( $request->get_param( 'schedule_note' ) ) : $existing->scheduleNote,
 			etransferEmail:  $request->has_param( 'etransfer_email' ) ? $this->nullableEmail( $request->get_param( 'etransfer_email' ) ) : $existing->etransferEmail,
 			cancellationCutoffHours: $request->has_param( 'cancellation_cutoff_hours' ) ? $this->nullableInt( $request->get_param( 'cancellation_cutoff_hours' ) ) : $existing->cancellationCutoffHours,
+			accessMode:      $request->has_param( 'access_mode' ) ? $this->accessMode( $request->get_param( 'access_mode' ), $existing->accessMode ) : $existing->accessMode,
 			isActive:        $request->has_param( 'is_active' ) ? (bool) $request->get_param( 'is_active' ) : $existing->isActive,
 			id:              $id,
 		);
@@ -212,6 +255,12 @@ class OfferingEndpoint {
 		return '' !== $email ? $email : null;
 	}
 
+	private function accessMode( mixed $value, string $fallback ): string {
+		$mode = Val::string( $value );
+
+		return in_array( $mode, Offering::VALID_ACCESS_MODES, true ) ? $mode : $fallback;
+	}
+
 	private function nullableInt( mixed $value ): ?int {
 		return ( null === $value || '' === $value ) ? null : Val::int( $value );
 	}

src/Offering/OfferingRepository.php

@@ -15,11 +15,11 @@ class OfferingRepository {
 	 * Column formats aligned to {@see columns()} (instructor_id, kind, title,
 	 * description, duration_minutes, price, currency, billing_mode, allow_weekly,
 	 * capacity, term_start, term_end, schedule_note, etransfer_email,
-	 * cancellation_cutoff_hours, is_active).
+	 * cancellation_cutoff_hours, access_mode, is_active).
 	 *
 	 * @var list<string>
 	 */
-	private const COLUMN_FORMATS = [ '%d', '%s', '%s', '%s', '%d', '%f', '%s', '%s', '%d', '%d', '%s', '%s', '%s', '%s', '%d', '%d' ];
+	private const COLUMN_FORMATS = [ '%d', '%s', '%s', '%s', '%d', '%f', '%s', '%s', '%d', '%d', '%s', '%s', '%s', '%s', '%d', '%s', '%d' ];
 
 	public function insert( Offering $offering ): int {
 		$this->db->insert(
@@ -63,16 +63,19 @@ class OfferingRepository {
 			'schedule_note'             => $offering->scheduleNote,
 			'etransfer_email'           => $offering->etransferEmail,
 			'cancellation_cutoff_hours' => $offering->cancellationCutoffHours,
+			'access_mode'               => $offering->accessMode,
 			'is_active'                 => $offering->isActive ? 1 : 0,
 		];
 	}
 
 	/**
-	 * Find offerings, optionally filtered by instructor, kind, and active state.
+	 * Find offerings, optionally filtered by instructor, kind, active state, and
+	 * access mode (e.g. `Offering::ACCESS_PUBLIC` to exclude invite-only classes
+	 * from the public catalogue).
 	 *
 	 * @return list<Offering>
 	 */
-	public function findAll( int $instructorId = 0, string $kind = '', ?bool $activeOnly = null ): array {
+	public function findAll( int $instructorId = 0, string $kind = '', ?bool $activeOnly = null, ?string $accessMode = null ): array {
 		$where  = [ '1 = 1' ];
 		$params = [];
 
@@ -91,6 +94,11 @@ class OfferingRepository {
 			$params[] = $activeOnly ? 1 : 0;
 		}
 
+		if ( null !== $accessMode ) {
+			$where[]  = 'access_mode = %s';
+			$params[] = $accessMode;
+		}
+
 		$whereClause = implode( ' AND ', $where );
 		$sql         = "SELECT * FROM %i WHERE {$whereClause} ORDER BY title ASC";
 

src/Plugin.php

@@ -14,6 +14,7 @@ use Unsupervised\Schedular\Booking\BookingPage;
 use Unsupervised\Schedular\Availability\AvailabilityRepository;
 use Unsupervised\Schedular\Booking\BookingRepository;
 use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
+use Unsupervised\Schedular\GroupClass\GroupAccessRepository;
 use Unsupervised\Schedular\GroupClass\GroupClassPage;
 use Unsupervised\Schedular\Offering\OfferingRepository;
 use Unsupervised\Schedular\Payment\BillingMethodResolver;
@@ -58,6 +59,7 @@ class Plugin {
 		$acceptances      = new AcceptanceRepository( $wpdb );
 		$invites          = new InviteRepository( $wpdb );
 		$enrollments      = new EnrollmentRepository( $wpdb );
+		$groupAccess      = new GroupAccessRepository( $wpdb );
 		$registrationGate = new RegistrationGate( $questions, $answers, $policies, $policyVersions, $acceptances );
 
 		$paymentRepo    = new PaymentRepository( $wpdb );
@@ -72,15 +74,15 @@ class Plugin {
 
 		$bookingPage      = new BookingPage();
 		$loginPage        = new LoginPage();
-		$registrationPage = new RegistrationPage( $invites, $policies, $policyVersions, $acceptances, $settings, $registrationMailer, $questions, $answers );
+		$registrationPage = new RegistrationPage( $invites, $policies, $policyVersions, $acceptances, $settings, $registrationMailer, $questions, $answers, $groupAccess );
 		$groupClassPage   = new GroupClassPage();
 
 		( new UpdateChecker() )->register();
 		( new RoleManager() )->register();
 		( new RegistrationLoginGate() )->register();
 		( new EmailConfirmationHandler( $settings, $registrationMailer ) )->register();
-		( new AdminMenu( $availability, $bookings, $offerings, $questions, $answers, $policies, $policyVersions, $policyService, $acceptances, $invites, $enrollments, $settings, $paymentRepo, $paymentService, $resolver ) )->register();
-		( new RestRegistrar( $availability, $bookings, $offerings, $questions, $policies, $policyVersions, $policyService, $registrationGate, $enrollments, $paymentService ) )->register();
+		( new AdminMenu( $availability, $bookings, $offerings, $questions, $answers, $policies, $policyVersions, $policyService, $acceptances, $invites, $enrollments, $groupAccess, $settings, $paymentRepo, $paymentService, $resolver, $registrationMailer ) )->register();
+		( new RestRegistrar( $availability, $bookings, $offerings, $questions, $policies, $policyVersions, $policyService, $registrationGate, $enrollments, $groupAccess, $paymentService ) )->register();
 		( new ShortcodeRegistrar( $bookingPage, $loginPage, $registrationPage, $groupClassPage ) )->register();
 		( new BlockRegistrar( $bookingPage, $loginPage, $registrationPage, $groupClassPage ) )->register();
 	}

src/RestRegistrar.php

@@ -9,6 +9,7 @@ use Unsupervised\Schedular\Booking\BookingEndpoint;
 use Unsupervised\Schedular\Booking\BookingRepository;
 use Unsupervised\Schedular\Booking\CancellationPolicy;
 use Unsupervised\Schedular\GroupClass\EnrollmentEndpoint;
+use Unsupervised\Schedular\GroupClass\GroupAccessRepository;
 use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
 use Unsupervised\Schedular\Offering\OfferingEndpoint;
 use Unsupervised\Schedular\Offering\OfferingRepository;
@@ -35,13 +36,13 @@ class RestRegistrar {
 	private EnrollmentEndpoint $enrollmentEndpoint;
 	private PaymentEndpoint $paymentEndpoint;
 
-	public function __construct( AvailabilityRepository $availability, BookingRepository $bookings, OfferingRepository $offerings, QuestionRepository $questions, PolicyRepository $policies, PolicyVersionRepository $policyVersions, PolicyService $policyService, RegistrationGate $gate, EnrollmentRepository $enrollments, PaymentService $paymentService ) {
+	public function __construct( AvailabilityRepository $availability, BookingRepository $bookings, OfferingRepository $offerings, QuestionRepository $questions, PolicyRepository $policies, PolicyVersionRepository $policyVersions, PolicyService $policyService, RegistrationGate $gate, EnrollmentRepository $enrollments, GroupAccessRepository $groupAccess, PaymentService $paymentService ) {
 		$this->availabilityEndpoint = new AvailabilityEndpoint( $availability, $offerings );
 		$this->bookingEndpoint      = new BookingEndpoint( $availability, $bookings, $offerings, $gate, $paymentService, new CancellationPolicy( new StudioSettings() ) );
-		$this->offeringEndpoint     = new OfferingEndpoint( $offerings );
+		$this->offeringEndpoint     = new OfferingEndpoint( $offerings, $groupAccess );
 		$this->questionEndpoint     = new QuestionEndpoint( $questions, $offerings );
 		$this->policyEndpoint       = new PolicyEndpoint( $policies, $policyVersions, $policyService );
-		$this->enrollmentEndpoint   = new EnrollmentEndpoint( $enrollments, $offerings, $gate, $paymentService );
+		$this->enrollmentEndpoint   = new EnrollmentEndpoint( $enrollments, $offerings, $gate, $paymentService, $groupAccess );
 		$this->paymentEndpoint      = new PaymentEndpoint( $paymentService );
 	}
 

src/Schema.php

@@ -66,6 +66,7 @@ class Schema {
                 schedule_note    VARCHAR(191)    DEFAULT NULL,
                 etransfer_email  VARCHAR(191)    DEFAULT NULL,
                 cancellation_cutoff_hours SMALLINT UNSIGNED DEFAULT NULL,
+                access_mode      VARCHAR(20)     NOT NULL DEFAULT 'public',
                 is_active        TINYINT(1)      NOT NULL DEFAULT 1,
                 created_at       DATETIME        NOT NULL,
                 PRIMARY KEY (id),
@@ -190,6 +191,7 @@ class Schema {
                 token            VARCHAR(64)     NOT NULL,
                 role             VARCHAR(32)     NOT NULL DEFAULT 'us_student',
                 kind             VARCHAR(10)     NOT NULL DEFAULT 'personal',
+                offering_id      BIGINT UNSIGNED DEFAULT NULL,
                 status           VARCHAR(20)     NOT NULL DEFAULT 'pending',
                 invited_by       BIGINT UNSIGNED DEFAULT NULL,
                 accepted_user_id BIGINT UNSIGNED DEFAULT NULL,
@@ -201,6 +203,22 @@ class Schema {
                 KEY email (email),
                 KEY status (status)
             ) {$charset};",
+
+			"CREATE TABLE {$prefix}us_group_access (
+                id            BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
+                offering_id   BIGINT UNSIGNED NOT NULL,
+                student_id    BIGINT UNSIGNED DEFAULT NULL,
+                email         VARCHAR(191)    NOT NULL DEFAULT '',
+                invite_id     BIGINT UNSIGNED DEFAULT NULL,
+                status        VARCHAR(20)     NOT NULL DEFAULT 'invited',
+                invited_by    BIGINT UNSIGNED DEFAULT NULL,
+                created_at    DATETIME        NOT NULL,
+                PRIMARY KEY (id),
+                KEY offering_id (offering_id),
+                KEY student_id (student_id),
+                KEY email (email),
+                KEY status (status)
+            ) {$charset};",
 		];
 	}
 }